Kaynam, In the case of uni-directional logical channels, the portNumber field is only available in the OpenLogicalChannel message, and so that is the one that must be used in all cases. I think that the terminal that receives the OpenLogicalChannel message will have access to the calling party information in the Q.2931 message, and so the port number will only be necessary to distinguish VCs opened by the same terminal. And I would hope that that terminal could choose portNumbers uniquely. Best regards Mike ************************************************************************ * Mike Nilsson Tel: +44 1473 645413 * * Video Processing Unit Fax: +44 1473 643791 * * Centre for Human Communications Email: mike.nilsson@bt-sys.bt.co.uk * * BT Laboratories [MLB3/11] * * Martlesham Heath * * Ipswich IP5 7RE * * UK * ************************************************************************

---------- From: Kaynam Hedayat[SMTP:Kaynam_Hedayat@PICTEL.COM] Sent: 10 February 1998 01:07 To: ITU-SG16@MAILBAG.INTEL.COM Subject: Question on H.323 V2 Annex C

Hi,

Section C.3.7.2 of H.323 V2 states that "The portNumber field of the OpenLogicalChannel message is conveyed in the B-HLI information element." Shouldn't the portNumber field of the OpenLogicalChannelAck message be conveyed in the B-HLI information element since the receiver of the OpenLogicalChannel is the endpoint which starts listening for the ATM connection with the given B-HLI? If it is in fact the endpoint that initiates the OpenLogicalChannel command who is responsible for choosing the B-HLI isn't there a possibility that the given B-HLI is already in use at the other endpoint? Thank you.

Kaynam